K2 Summit and K2 Base Direct Detection Camera User's Guide
30
Operation of the K2 Direct Detection System
K2 Imaging
Linear Mode Operation
View Mode
Specimen viewing and single-frame acquisition are organized exactly as for traditional CCD
cameras. View and Acquire can each be set up with preferences for unprocessed, dark-
subtracted or gain-normalized. Subareas can be selected.
View
mode allows the user to observe
live
(continuous) images on the monitor. The setup has
two operating modes which are preset for easy use.
Search
mode displays a continuous (low resolution) image with the entire sensor field of
view. This is to allow the user to quickly conduct a sample search using the camera.
Focus
mode displays a continuous image at higher resolution than the Search image. Fine
adjustment of focus setting can be done with this operation mode.
figure 1-32. View Mode dialog
Counted and Super-Resolution Mode Operation
Dose Rate Considerations
20 electrons/sensor pixel/sec is considered the maximum dose for quality counted imaging.
(16-18 counts/pixel/second)
The dose recommended for high quality imaging is 10e
-
/pixel/second (8-9 counts/pixel/sec.).
In Super-Resolution mode, this dose rate corresponds to 2.5 electrons per Super-Resolution
pixel per second. (~2 counts/Super-Resolution pixel/second)
